New 6-aminopenicillanic acid derivatives, methods for producing and compositions containing same

ABSTRACT

New compounds of the general formula   in which R1, R2, R3 and R4 represent an aliphatic hydrocarbon radical, a mono- or bicyclic aryl radical, an aralkyl radical, a cycloalkyl radical, a cycloalkylalkyl radical, a heterocyclic radical or a heterocyclically substituted alkyl radical; R1 furthermore represents an acyl or unsubstituted or substituted carbamyl radical, in which case R2 can also be hydrogen; each of the radicals R1, R2, R3 and R4 can together with one or more of the other radicals form a heterocyclic ring system; R1 and R2 together represent an alkylidene radical attached to the nitrogen atom with a double bond; R4 and R5 can also be hydrogen and R5 can be unsubstituted or substituted alkyl or aralkyl radical. The compounds of the invention possess valuable antibacterial activity and the toxicity is extremely low.

United States Patent [19] Lund [ 51 Oct. 14, 1975 [75] inventor: FrantzJohannes Lund, Lyngby,

Denmark [73] Assignee: Lovens Kerniske Fabrik Produktionsaktieselskab,Ballerup, Denmark 22 Filed: Feb. 19, 1974 21 Appl. No.: 443,191

[30] Foreign Application Priority Data Feb. 27, 1973 United Kingdom9592/73 [52] US. Cl 260/306.7 C; 260/239.1; 424/271 [5 1] Int. Cl. C07D499/02 [58] Field of Search 260/239.l, 306.7 C

[56] References Cited UNITED STATES PATENTS 3,l98,804 1965 Johnson et al260/306.7

FOREIGN PATENTS OR APPLICATIONS 1,293,590 1972 United Kingdom 260/239.l

Primary ExaminerGerald A. Schwartz Attorney, Agent, or Firm-Jackson,Jackson and Chovanes ABSTRACT New compounds of the general formula cooR,

in which R R R and R represent an aliphatic hydrocarbon radical, amonoor bicyclic aryl radical, an aralkyl radical, a cycloalkyl radical,a cycloalkylalkyl radical, a heterocyclic radical or a heterocyclicallysubstituted alkyl radical; R furthermore represents an acyl orunsubstituted or substituted carbamyl radical, in which case R can alsobe hydrogen; each of the radicals R R R and R, can together with one ormore of the other radicals form a heterocyclic ring system; R and Rtogether represent an alkylidcne radical attached to the nitrogen atomwith a double bond; R and R, can also be hydrogen and R can beunsubstituted or substituted alkyl or aralkyl radical.

The compounds of the invention possess valuable antibacterial activityand the toxicity is extremely low.

10 Claims, No Drawings NEW 6-AMINOPENICILLANIC ACID DERIVATIVES, METHODSFOR PRODUCING AND COMPOSITIONS CONTAINING SAME This invention relates tohitherto unknown derivatives of 6-aminopenicillanic acid, and topharmaceutically acceptable salts thereof.

The compounds of the invention which are valuable in the human andveterinary practice, have the general formula:

in which R R R and R represent an aliphatic hydrocarbon radical, amonoor bicyclic aryl radical, an aralkyl radical, a cycloalkyl radical,a cycloalkylalkyl radical, a heterocyclic radical or a heterocyclicallysubstituted alkyl radical; R furthermore represents an acyl orunsubstituted or substituted carbamyl radical, in which case R can alsobe hydrogen; each of the radicals R R R and R, can together with one ormore of the other radicals form a heterocyclic ring system; R and Rtogether represent an alkylidene radical attached to the nitrogen atomwith a double bond; R and R can also be hydrogen and R can be anunsubstituted or substituted alkyl or aralkyl radical.

More particularly, R, to R represent an aliphatic hydrocarbon radical inwhich the carbon chain can be straight or branched, saturated orunsaturated, e.g. methyl, ethyl, propyl, isopropyl, butyl, sec.butyl,tert- .butyl, pentyl, hexyl, dodecyl, allyl, butenyl, pentenyl,propargyl; a monoor bicyclic aryl radical, e.g. a phenyl radical or anaphtyl radical; an aralkyl radical, such as monoor bicyclic aralkylradical, e.g. benzyl, phenylethyl, lor 2-naphthylmethyl; a cycloalkyl orcycloalkyl-alkyl radical, in which the cycloalkyl group can have from 3to ring members and can be saturated or have one or two double bonds,e.g. cyclopentyl, cyclohexyl, l-adamantyl, l-bicyclo (2.2.2)octyl,cyclopentenyl and cyclohexenyl, cyclopentylmethyl, cyclohexylmethyl,cyclopentenylethyl, cyclohexenyl methyl, etc; a heterocyclic radical ora heterocyclically substituted alkyl radical in which the heterocyclicpart can have from 5 to 10 atoms in the ring and can contain oxygen,sulphur, and/or nitrogen atoms in all of which the hetero atoms may beplaced in any of the available positions, and such heterocyclic radicaloptionally being more or less hydrogenated, e.g. pyridyl, pyrazinyl,pyrimidyl, pyrrolidyl, piperidyl, morpholinyl, pyrazolyl, pyrazolinyl,pyrazolidinyl, thiazinyl, furyl, thienyl, quinolyl; each of the radicalsR to R, can together with one or more of the other radicals representheterocyclic radicals having from 5 to 8 ring atoms and optionallycontaining other hetero atoms in the ring, such as S, O and/or N,forming more or less hydrogenated ring systems e.g. pyrazolinyl,pyrazolidinyl, 1,2,3- ,6-tetrahydropyridazinyl, l ,4,5 ,6-

tetrahydropyridazinyl, hexahydropyridazinyl, piperidyl, morpholinyl,hexahydro-lH-azepin-l-yl, or hexahydro-l(2H)-azocinyl.

When R, represents acyl, it may in particular represent an aliphatic,alicyclic, aromatic, araliphatic or heterocyclic acyl radical, such asan acetyl, propionyl, butyryl, pivaloyl, cyclohexylacetyl, benzoyl,phenylacetyl, picolinyl, nicotinyl, furylacetyl or thienylacetylradical. When R represents a substituted carbamyl, the substituents arepreferably lower alkyl.

The radicals R to R may be further substituted with halogen atoms, analkyl, hydroxy, alkoxy, aryloxy, alkylthio, arylthio group, an acylgroup, a carboxy, carbalkoxy, carbamyl, carbamido, cyano or sulfonylgroup, an azido, aminoor substituted amino group.

More particularly, R besides being hydrogen stands for an alkyl radical,e.g. a methyl or butyl radical, an aralkyl radical, e.g. a benzylradical, a cycloalkyl or cycloalkyl-alkyl radical, eg a cyclopentyl or acyclohexylmethyl radical, an alkyl radical substituted with halogen,alkoxy, alkanoyl, aroyl, cyano, or a carbalkoxy group, e.g. B, B,B-trichloroethyl, methoxymethyl, acetonyl, phenacyl, cyanomethyl,carbethoxymethyl, or dicarbethoxymethyl; R further represents anacyloxymethyl radical the acyl part of which being e.g. an aliphatic,alicyclic, aromatic, ar-aliphatic or heterocyclic acyl radical, such asacetyl, propionyl, butyryl, pivaloyl, cyclohexylacetyl, benzoyl,phenylacetyl, picolinyl, nicotinyl, furylacetyl and thienylacetyl.

Further R represents one of following radicals:

in which radicals R represents aliphatic, cycloaliphatic, aryl, aralkyl,or heterocyclic radicals all of these radicals optionally beingsubstituted by one or more radicals selected from the group consistingof nitro, azido, amino, substituted amino, such as methylamino,diethylamino, and acetamido, alkyl, trifluoroalkyl, halogen, alkoxy,aryloxy, alkylthio and arylthio radicals;

R represents hydrogen, methyl or ethyl;

X represents --O-, NI-I or -S-.

As examples of radicals falling within the above definitions and thedefinitions used in the present specification, mention may especially bemade of: alkyl: methyl, ethyl,'p ropyl, isopropyl, butyl, isobutyl,tert-butyl, pentyl, hexyl, heptyl, octyl and 2-ethylhexyl; cycloalkyl:cyclopropyl, cyclobu tyl, cyclopentyl, cyclohexyl and cycloheptyl;cycloalkyl-alkyl:

alkoxy: methoxy, ethoxy, propyloxy, isopropyloxy, butoxy and isobutoxy;halogen: fluorine, chlorine and bromine;

aryl: phenyl, tolyl, naphthyl;

aralkyl: benzyl, phenethyl and naphthylmethyl; alkylthio: methylthio,ethylthio and butylthio; heterocyclic radicals:

Continued s-l hcxahydrol H-axcpin- I yl mcthylc'ncamino l-pcnicillunicacid (a compound according to British Patent 5 No. 1.293.590)

Further, no cross resistance has been shown between the presentcompounds and the previously known amidinopenicillanic acid derivatives,e.g. as described in the above mentioned British patent.

For certain medical purposes it will be advantageous N N ll l lT N T Iif l l 1' I. l 111 j l ll i H2 2 \N/ 2 N 2 I I I H H H Whenever theexpression lower is used in the foregoing and in the following inconnection with an organic radical it indicates a content of from 1 to 6atoms.

The compounds of formula I may be isolated as such or in the form of asalt with a pharmaceutically acceptable acid, such as hydrochloric acid,phosphoric acid, nitric acid, p-toluenesulfonic acid, acetic acid,propionic acid, citric acid, tartaric acid, maleic acid, etc. When Rstands for hydrogen the compounds of formula 1 may be isolated as thezwitterion or as a salt, e.g. the alkali metal salts and the ammonium oramine salts, or salts with strong acids, such as hydrochloric acid ormethanesulfonic acid.

The invention comprises all possible isomeric forms of the compounds offormula 1, depending on the different substituents, whereas the6-aminopenicillanic acid moiety has the configuration of that obtainedby the fermentation process.

The compounds of the invention possess valuable antibacterial activityand the toxicity is extremely low.

The antibacterial effect of the compounds of the in- I Concentrationrequired for 50% inhibition, (pg/ml) 6-[(N-( hexahydrol H-azepin--l-yl)-cthylamino)-methylcncaminol-penicillanic acid (a compoundaccording to the present invention) to use the free acids or theirsalts, whereas it for other purposes will be more favourable to use theeasily bydrolyzable esters, which in the organism will be chemically orenzymatically hydrolyzed to the corresponding free acids. In other casesthe less hydrolyzable esters will be preferred in order to obtainparticular distribution in the body.

For instance in some cases the afore-mentioned acyloxyalkyl esters offormula 1 are absorbed more efficiently after oral administration thanthe corresponding free acids. After the absorption these esters arehydrolyzed under the influence of enzymes present in blood and tissueswith liberation of the corresponding free acids, which generally have amore pronounced antibacterial activity than the esters.

The invention also comprises methods for the preparation of the abovedescribed compounds. In one method the compounds are prepared byreacting a 6- aminopenicillanic acid derivative of the general formulall:

in which R is as defined above for R or stands for a trialkylsilylradical, e.g. a trimethylsilyl radical, with a compound of the formulaIll:

CF SO or another suitable anion. The reaction is performed in an inertorganic solvent such as chloroform and preferably in the presence of oneor two equivalents of a tertiary amine, e.g. trimethylamine,triethylamine, N,N-diisopropylethylamine or N- methylmorpholine.

In case that R in the starting material of formula II is hydrogen, thefinal compounds of formula I are produced in the form of theirzwitterions. If R stands for a trialkylsilyl radical, then the freeacids of formula I are obtained directly or after an alcoholysis.

The reaction may be performed at or below room temperature but usuallyunder cooling, and the reaction mixture is in most cases left standingovernight. The reaction product of formula I is isolated by wellknownmethods.

The compounds of formula III are new compounds and are prepared bythioacylating in known manner a hydrazine of the formula IV:

in which R,, R and R are as defined above, to form a reaction product ofthe general formula V:

in which R R R and R are as defined before. This product is alkylated bytreatment with an alkylating agent of the formula R X, in which R and Xare as defined above, in a suitable solvent, e.g. ether, acetone, oralcohols at about room temperature or at slightly elevated temperaturesand the reaction product of formula III is isolated in known manner.

In another method, the compounds of the invention are prepared byreacting the hydrazine of formula IV with a reactive derivative of a6-acylamino-penicillanic acid ester. Such a reactive derivative is forinstance obtained by reacting a compound of formula VI:

in which R and R are as defined before except that R, cannot behydrogen, with a halogenating agent, e.g. phosphorous pentachloride, inthe presence of a tertiary organic base, for instance quinoline. Thereaction is performed without isolation of the intermediate formed bythe process, which in the example mentioned above is supposed to be animide chloride of the compound of formula VI. The reactions areperformed below or at room temperature and in the presence of an inertsolvent, e.g. chloroform. As another reactive derivative of thecompounds of formula VI an imido ester can be mentioned, which can beprepared by reacting the imide halogenide mentioned above with a loweraliphatic alcohol in the presence of a tertiary organic amine, e.g.triethylamine.

In another embodimentof this method, the compounds of formula I in whichR, is hydrogen are prepared by reacting a o-aminopenicillanic acidderivative of the above formula II with a compound of the formula VI]:

in which X is a halogen atom, preferably chlorine, Y is an oxygen or asulphur atom, and R is a lower alkyl or a benzyl radical, therebyforming a reactive derivative ofa compound of formula VI, said reactivederivative having the formula VIII:

in which R R,,, and Y have the above meanings. Without isolation of thereaction product of formula VIII, a hydrazine of the above formula IV isadded to the reaction mixture, whereby a compound of formula I isobtained. The reaction is preferably performed in an inert organicsolvent, suchas diethyl ether, tetrahydrofuran, diethylene glycoldimethyl ether, or benzene at or below room temperature. The first partof the reaction proceeds rapidly and after the addition of the hydrazineof the formula IV, the reaction mixture is placed at or below roomtemperature until the reaction has finished.

The starting materials of formulae II, IV, VI and VII are known or canbe prepared by conventional methods for preparing analogous knowncompounds.

The reaction products of formula I can be purified and isolated in usualmanner and may be obtained either in the free state or in the form of asalt.

The free acid (R5=H) can, in addition to the methods described before,be obtained from some of the esters by an enzymatic hydrolysis or a mildhydrogenolysis of preferably the benzyl esters using a noble metalcatalyst such as a palladium-on-carbon catalyst, and if the free acid isthe reaction product, the esters can be prepared therefrom byesterification methods known from the literature.

It is a further object of the present invention to providepharmaceutical compositions which are useful in the treatment ofinfectious diseases in the human and veterinary practice.

With this object in view, the compositions of the invention contain asan active component at least one member selected from the groupconsisting of compounds of the formula I and salts thereof withnontoxic, pharmaceutically acceptable acids and bases (the latter incase R =hydrogen), together with solid or liquid pharmaceutical carriersand/or diluents.

In the said compositions, the proportion of therapeutically activematerial to carrier substance can vary'between 1% and by weight. Thecompositions can be worked up to various pharmaceutical forms ofpresentation, such as tablets, pills, dragees, suppositories, capsules,sustained-release tablets, suspensions, injection medicine and the likecontaining the compounds of formula I or their atoxic salts, mixed withcarriers and/0r diluents.

Pharmaceutical organic or inorganic, solid or liquid carriers and/ordiluents suitable for oral, enteral or parenteral administration can beused to make up compositions containing the present compounds. Gelatine,

lactose, starch, magnesium stearate, talc, vegetable and animal fats andoils, gum, polyalkylene glycol, buffers or other known carriers and/ordiluents for medicaments are all suitable.

The preferred salt of the compounds of formula I is the hydrochloride,but salts with other inorganic or organic acids including antibioticallyactive acids may be used, e.g. the phosphate, the acetate or thephenoxymethylpenicillinate. Furthermore, the compositions may containother pharmaceutically active components which can appropriately beadministered together with the ester in the treatment of infectiousdiseases, such as other suitable antibiotics.

The free acids of formula I, as such or in the form of their salts inbuffered solutions, are generally administered parenterally, whereas theeasily hydrolyzable esters included in formula I are never givenparenterally but preferably orally or in another suitable manner.

As indicated above, the compounds of formula I and their salts may beworked up to pharmaceutical forms of presentation including suspensionsand non-aqueous ointments and creams. A pharmaceutical preparation fororal treatment may be in the form of a suspension of a compound offormula (I) as such or in the form of a sparingly soluble salt with apharmaceutically acceptable acid, the preparation containing from 20 to100 mg per ml of a non-aqueous vehicle. A pharmaceutical preparation fortopical treatment may be in the form of a non-aqueous ointment or creamcontaining a compound of formula (I) in an amount of from /2 to g per100 g of preparation.

Another object of the invention resides in the selection of a dose ofthe compounds of the invention which dose can be administered so thatthe desired activity is achieved without simultaneous secondary effects.In human therapy, the compounds and their salts are convenientlyadministered (to adults) in dosage units containing not less than 50 mgand up to 1000 mg, preferably from 250 to 750 mg, calculated as thecompound of formula I.

By the term dosage unit is meant a unitary, i.e. a single dose which iscapable of being administered to a patient, and which may be readilyhandled and packed, remaining as a physically stable unit dosecomprising either the active material as such or a mixture of it withsolid or liquid pharmaceutical diluents or carriers.

In the form of a dosage unit, the compound may be administered once ormore times a day at appropriate intervals, always depending, however, onthe condition of the patient, and in accordance with the prescriptionmade by the medical practitioner.

Thus a daily dose will preferably be an amount of from 1 to 3 g of acompound of formula I.

If the composition is to be injected, a sealed ampoule, a vial or asimilar container may be provided containing a parenterally acceptableaqueous or oily injectable solution or dispersion of the active materialas the dosage unit.

The parenteral preparations are in particular useful in the treatment ofconditions in which a quick response to the treatment is desirable. Inthe continuous therapy of patients suffering from infectious diseases,the tablets or capsules may be the appropriate form of pharmaceuticalpreparation owing to the prolonged effect obtained when the drug isgiven orally, in particular in the form of sustained-release tablets.

In the treatment of infectious diseases, such tablets may advantageouslycontain other active components, as mentioned hereihbefore.

Still another object of the invention is to provide a method of treatingpatients suffering from infectious diseases, the method comprisingadministering to adult. patients from 0.5 g to 5 g per day, preferablyfrom 1 to 3 g per day, of a compound of the formula I or an equivalentamount of a salt as defined before of a compound of the formula I.Preferably, the compound is given in the form of the dosage unitsaforesaid.

The invention will be further described in the following Examples whichare not to be construed as limiting the invention.

EXAMPLE 1 Pivaloyloxymethyl6-trimethylhydrazinomethyleneaminopenicillanate nitrate To a solution ofpivaloyloxymethyl 6- aminopenicillanate (6.6 g) in dry ether (100 ml)was added isopropyl formimidate hydrochloride (2.5 g). The suspensionwas stirred for 20 minutes at room temperature. After cooling withice-water trimethylhydrazine (1.5 g) was added. The reaction mixture waskept at 05C for 16 hours and filtered. The filtrate was extracted withdiluted hydrochloric acid 100 ml) at a pH of about 2.5. The aqueousphase was made alkaline with sodium bicarbonate and extracted with ethylacetate 100 ml), which, was dried over magnesium sulfate.

After removal of the solvent in vacuo the residue was redissolved inether ml), filtered again, and the filtrate evaporated in vacuo. Theoily residue was taken up in ethanol (20 ml) and a solution ofconcentrated nitric acid (0.5 ml) in isopropanol (5 ml) was added at 0Cfollowed by ether (about 50 ml). The crystalline precipitate wasisolated and melted at l59l60C. A recrystallization fromethanol/diisopropyl ether gave an analytically pure product with amelting point of [a] 197 (c=l, 96% v/v ethanol) EXAMPLE 2Pivaloyloxymethyl 6-[(N-allyl-N', N-dimethylhydrazino)-methyleneamino]-penicillanate nitrate Pivaloyloxymethyl o-aminopenicillanate (3.3 g) and.isopropyl formimidate hydrochloride (1.25 g) were stirred in dry ether(50 ml) for half an hour at room temperature. At O-5CN-allyl-N',N-dimethylhydrazine (l g) was added. The mixture was left for16 hours at this temperature. After filtration the filtrate wasextracted with diluted hydrochloric acid (50 ml) at pH 23. The aqueousphase was made alkaline with sodium bicarbonate and extracted with ether(75 ml). After drying, the ethereal phase was evaporated in vacuo. Theresidue was dissolved in ether (25 ml) and the nitrate precipitated bythe addition of a solution of concentrated nitric acid (0.2 ml) inethanol (5 ml). The precipitate was recrystallized from acetone-etherand from isopropanol yielding the analytically pure product with amelting point of I56.5-l57C.

[a],, 182 (0 1, 96% v/v ethanol).

EXAMPLE 3 Pivaloyloxymethyl 6-[(N-benzyl-N',N-dimethylhydrazino)-methyleneamino]-penicillanate oxalate A.N-Benzyl-N',N-dimethylthioformohydrazide A solution of ethyl thioformate(2.5 g) in dry ether ml) was slowly added to a solution of N-benzyl-N',N'-dimethylhydrazine (4.1 g) in ether (40 ml) at 0-5C with stirring.The solution was kept at room temperature for 64 hours and extractedwith 1 N hydrochloricacid (50 ml) and water (50 ml) at 05C.

After drying, the ether was removed in vacuo.

B. N-Benzyl-N,N,S-trimethylthioformohydrazidium iodide The crude product(2 g) and methyl iodide (0.95 ml) were dissolved in ether (50 ml) andkept 16 hours at room temperature to precipitate a crude product whichwas used in the next step without purification.

C. Pivaloyloxymethyl 6-[(N-benzyl-N,N'-dimethylhydrazino)-methyleneamino]-penicillanate oxalatePivaloyloxymethyl 6-aminopenicillanate hydrochloride (1.45 g) andN,N-diisopropylethylamine (2 ml) were dissolved in dry chloroform (30ml). The abovementioned crude product (1.3 g) was added and the reaction mixture kept in an ice-box overnight. After evaporation in vacuothe residue was triturated with ether (50 ml). The precipitate wasfilteredoff and the filtrate extracted with diluted hydrochloric acid(30 ml pH z 2). The aqueous phase was made alkaline with sodiumbicarbonate and extracted with ether (50 ml) which was dried andevaporated in vacuo. The residue was dissolved in acetone (10 ml).Addition of a solution of anhydrous oxalic acid in acetone precipitatedthe salt which was recrystallized from acetone. The analytically purecompound had a melting point of 145C. [a] 174 (c=1, 96% v/v ethanol).

EXAMPLE 4 Pivaloyloxymethyl 6-[ N'-acetyl-N -isopropylhydrazinomethyleneamino] -penicillanate To a suspension of pivaloyloxymethyl 6-aminopenicillanate p-toluenesulfonate (11 g) in dry benzene (100 ml) wasadded 3.45 ml of N,N- diisopropylethylamine with stirring. To theresulting solution propyl formimidate hydrochloride (2.8 g) was added,and the reaction mixture was stirred for half an hour at roomtemperature. The solvent was removed inv vacuo and the residue wastriturated with ether (100 ml). The solid formed was removed byfiltration. N'- lsopropylacetohydrazide (2.4 g) was added to thefiltrate which was kept at room temperature for 48 hours and thenextracted with diluted hydrochloric acid (50 ml pH z 2). The aqueousphase was made alkaline with sodium bicarbonate and extratedwith ether(75 ml). The ether was removed in vacuo and the residue crystallized bytrituration with water. After a recrystallization from di-n-butyl ether,the melting point was 90-100C. The crude product was dissolved indiluted hydrochloric acid (50 ml,- pH 2) and extracted with methylenechloride and ether. The aqueous phase was made alkaline with sodiumbicarbonate and taken up in ether which was removed in vacuo. Theresidue was triturated with water to yield the analytically purecompound with a melting point of l03104C. [a] 197 (c=1, 96% v/vethanol).

EXAMPLE 5 Pivaloyloxymethyl 6-[(N-carbamyl-N,N -dimethylhydrazino)-methyleneamino]-penicillanate A solution of pivaloyloxymethyl 6-aminopenicillanate p-toluenesulfonate (15 g) and N,N-diisopropylethylamine (5.15 ml) in dry benzene (150 ml) was treated withpropyl formimidate hydrochloride (4.2 g) as in Example 4. The benzenewas removed in vacuo and the residue triturated with ether. Afterfiltration the ether was removed in vacuo. The residue (8 g) wasdissolved in tetrahydrofuran (150 ml). 1,2-Dimethylsemicarbazide (2.1 g)was added and the resulting solution kept at room temperature for 20hours. The solvent was removed in vacuo and the residue triturated withether. After filtration the filtrate was extracted with dilutedhydrochloric acid (50 ml, pH 2). The aqueous phase was made alkalinewith sodium bicarbonate. The crystalline precipitate thereby formed wasrecrystallized from ethyl acetate -petroleum ether to yield theanalytically pure compound with a melting point of 151151.5C.

[a],,': (c=1, 96% v/v ethanol).

EXAMPLE 6 Pivaloyloxymethyl6-[(5-methyl-2-pyrazolin-1-y1)-methyleneamino]- penicillanatePivaloyloxymethyl 6-aminopenicillanate (3.3 g) and isopropyl formidatehydrochloride (1.25 g) were stirred in dry ether (50 ml) for half anhour at room temperature. At 05C S-methyl-Z-pyrazoline (0.85 g) wasadded. The mixture was left for 40 hours at this temperature. Afterfiltration, the filtrate was evaporated in vacuo. The residue was takenup in ether and extracted with diluted hydrochloric acid at pH z 2-3.The aqueous phase was made alkaline with sodium bicarbonate andextracted with ether. The ethereal phase was dried and evaporated invacuo to leave an oil which did not crystallize. According to the NMRspectrum 10% w/v CDCl the product consists of a 1:1 mixture of twostereoor rotationisomers:

C(CHJ)3 18 H s at 1.23 NCH-CH;, 6 H d at 1.36 (J=6) 6 H S at 1.51

(2)( a)z 3 H S 1 at 1.65

I 3 H s at 1.69

N=CH-CH 4 H m at 2.5-3.5

l N-Q-CH 2 H m at 4.0-4.8

1 H s at 4.42 C13)H 3 g 1 H s at 4.45

l H bd at 5.07 (J=5) an 3 1H bd at 5.15 (.l=5) C H 2 H d at 5.55 (.1=5)

d at 5.80 (1 5) OCH O 4 H ABq d at 5.92 (J=5) N-N= (ll CH 2 H m at 6.78l H bs at 8.27 N-CH=N 1 H bs at 8.40

In this and the following Examples the chemical shifts are given as ppmin 8 values with TMS (0 ppm) as internal standard. Coupling constants(J) are in cps.

EXAMPLE 7 Pivaloyloxymethyl 6-[(N-(hexahydro-l H-azepinl -yl)-ethylamino)- methyleneaminol-penicillanate A.Hexahydro-l-(methyleneamino)-lH-azepine Formalin (44 ml) was slowlyadded to l-aminohexahydro-lH-azepine (38 ml) with stirring at 2030C. Themixture was stirred for 3 hours at room temperature and saturated withsolid sodium hydroxide with cooling. The organic phase was separated,dried over magnesium sulfate and distilled. The boiling point was6869C/l0 mm Hg.

B. l-( Ethylamino )hexahydro-l H-azepine hydrochloride 1 To the Grignardreagent prepared from magnesium (3.6 g) and methyl iodide (92 ml) in drydibutyl ether (20 ml), the above-mentioned product (14.8 g) in dibutylether (15 ml) was slowly added with stirring at 5060C. The mixture wasstirred at 85-90C for 2 hours. The next day the mixture was poured onconcentrated hydrochloric acid (25 ml) and ice (125 g). The aqueousphase was separated and concentrated in vacuo. Concentrated sodiumhydroxide solution (40 ml) was added with stirring and cooling. Themixture was extracted with ether (3 X 100 ml). The organic phase wasdried and distilled to yield the compound with a boiling point of65-66Cl10 mm Hg.

This compound (9.6 g) was dissolved in ether (150 ml). At -5C, hydrogenchloride in isopropanol (8 N, 8.5 ml) was added to yield the purehydrochloride with a melting point of l26l 27C.

C. Pivaloyloxymethyl6-[(N-(hexahydro-lH-azepin-lyl)-ethylamino)-methyleneamino]-penicillanatePivaloyloxymethyl 6-aminopenicillanate (6.6 g) and propyl formimidatehydrochloride (2.8 g) were stirred in dry ether 100 ml) for half an hourat room temperature. At 0-5C, l-(ethylamino)hexahydro-1H-azepine (2.8 g)(liberated from a solution of the hydrochloride in methanol byneutralization with sodium methoxide followed by removal of the solventin vacuo and extraction with ether) was added. The mixture was left atthis temperature during the night.

- The reaction mixture was extracted twice with water and finally withdiluted hydrochloric acid (pH z 2). The last extract was made alkalinewith sodium bicarbonate and extracted with ether. The etheral phase wasextracted with diluted hydrochloric acid (50 ml). The

aqueous phase was extracted with methylene chloride (2 X 50 ml) and theorganic phase was dried and evaporated in vacuo. The residue was treatedwith charcoal (30 mg) in petroleum ether (30 ml) and the filtrate wasevaporated in vacuo. The residue did not crystallize.

NMR spectrum w/v CDCl EXAMPLE 8 Pivaloyloxymethyl 6-[N-piperidinoethylamino )-methyleneamino penicillanatc A.l-(methyleneamino)piperidine By following the procedure of Example 7 (A)and replacing l-aminohexahydro-lH-azepine by 1- aminopiperidine thecompound was obtained with a boiling point of 44-46C/l0 mm Hg. B.l-(Ethylamino)piperidine hydrochloride By following the procedure ofExample 7 (B) and replacing hexahydro-l-(methyleneamino)-l H-azepine byl-(methyleneamino)piperidine the hydrazine was obtained with a boilingpoint of 44-45C/1 0 mm Hg. The melting point of the hydrochloride wasl4ll42C. C. Pivaloyloxymethyl 6-[(N-piperidinoethylamino)-methyleneaminol-penicillanate By following the procedure of Example 7(C) and replacing l-(ethylamino)hexahydro-lH-azepine by l- (ethylamino)piperidine, the compound was obtained as an oil which did notcrystallize.

EXAMPLE 9 Pivaloyloxymethyl 6-[(N-ethyl-N,N-dipropylhydrazino)-methyleneamino]-penicillanate A. Formaldehyde dipropylhydrazone Byfollowing the procedure of Example 7 (A) and replacingl-aminohexahydro-l H-azepine by N,N- dipropylhydrazine, the compound wasobtained with a boiling point of 4446C/l0 mm Hg. B.N-Ethyl-N',N'-dipropylhydrazine By following the procedure of Example 7(B) and replacing hexahydrol -(methyleneamino l H-azepine byformaldehyde dipropylhydrazone, the hydrazine was obtained with aboiling point of 45-50C/l0 mm Hg. C. Pivaloyloxymethyl 6-[(N-ethyl-N,N'-

dipropylhydrazino)-methyleneamino]-penicillanate By following theprocedure of Example 7 (C) and replacingl-(ethylamino)hexahydro-lH-azepine by N- ethyl-N,N'-dipropylhydrazine,the compound was obtained as an oil which did not crystallize.

EXAMPLE l0 Acetoxymethyl 6-[ (N-ethyl-N',N -dibutylhydrazinomethyleneamino]-penicillanate A. Formaldehyde dibutylhydrazone Byfollowing the procedure of Example 7 (A) and replacingl-aminohexahydro-lH-azepine by N,N- dibutylhydrazine the compound wasobtained with a .boiling point of 89-92C/20 mm Hg.

B. N-Ethyl-N',N-dibutylhydrazine By following the procedure of Example 7(B) and replacing hexahydrol methyleneamino 1 H-azepine by formaldehydedibutylhydrazone the hydrazine was obtained with a boiling point of82-86C/ 15-1 8 mm Hg. C. Acetoxymethyl 6-[(N-ethyl-N',N'-

dibutylhydrazino)-methyleneaminol-penicillanate By following theprocedure of Example 7 (C) and replacingl(ethylamino)hexahydro-lH-azepine by N- ethyl-N',N'-dibutylhydrazine andpivaloyloxymethyl -aminopenicillanate with acetoxymethyl 6-aminopenicillanate, the compound was obtained as an oil.

EXAMPLE 11 l'-Ethoxycarbonyloxyethyl6-trimethylhydrazinomethyleneaminopenicillanate By following theprocedure of Example 1 and replacing ivaloyloxymethyl6-aminopenicillanate by 1'-ethoxycarbonyloxyethyl 6-aminopenicillanate,the compound was obtained as an oil.

EXAMPLE 12 Benzyl 6-[(N-allyl-N,N'-dimethylhydrazino)-methyleneamino]-penicillanate hydrochloride By following the procedureof Example 2 and replacing pivaloyloxymethyl 6-aminopenicillanate bybenzyl 6-aminopenicillanate, the compound was obtained as an amorphouspowder.

EXAMPLE l3 Butyl 6-[(2-methylpyrazolidin-1-yl)-methyleneamino]-penicillanate By following the procedure of Example 6 and replacingpivaloyloxymethyl -aminopenicillanate by butyl 6-aminopenicillanate and5-methyl-2-pyrazoline with l-methylpyrazolidine, the compound wasobtained as an oil which did not crystallize.

EXAMPLE 14 Pivaloyloxymethyl6-(a-trimethylhydrazino-B-phenylethylideneamino penicillanate A.N,N,N-Trimethylphenylthioacetohydrazide hydrochloride Carboxymethyldithiophenylacetate (17.9 g) was stirred with ice-water (40 ml) and 2 Nsodium hydroxide (37.5 ml) at O-5C. To the filtered solution,trimethylhydrazine (6.5 g) was added. The mixture was stirred for 2hours at room temperature. The precipitate formed was sucked off, washedwith water, and airdried. The melting point was 6264C. The hydrochloridewas prepared by dissolving this product (4.2 g) in ether (350 ml) andadding hydrogen chloride in isopropanol (2.5 ml, 8 N). It wasrecrystallized from ethanolether. The melting point was 154155C. B.N,N',N'-S-Tetramethylphenylthioacetohydrazidium iodide This compound wasprepared from methyl iodide (1.9 ml) andN,N,N-trimethylphenylthioacetohydrazide (4.2 g) in ether at roomtemperature. The crude product was used in the next step (cp. Example3(B)) C. Pivaloyloxymethyl 6-[a-trimethylhydrazino-B-phenylethylideneamino]-penicillanate This compound was prepared byfollowing the procedure of Example 3 (C) and replacing N-benzyl-N,N',S-trimethylthioformohydrazidium iodide by N,- N N'S-tetramethylphenylthioacetohydrazidium iodide. The product was an oilwhich did not crystallize.

EXAMPLE Pivaloyloxymethyl 6-(a-trimethylhydrazino-Z-thenylideneamino)-penicillanate By following the procedure of Example 14 and replacingcarboxymethyl dithiophenylacetate by carboxymethyl2-thiophenedithiocarboxylate, the product was obtained as an oil.

EXAMPLE 16 I Pivaloyloxymethyl 6-(a-trimethylhydrazino-p-chlorobenzylideneamino penicillanate By followingthe procedure of Example 14 and replacing carboxymethyldithiophenylacetate by carboxymethyl p-chlorodithiobenzoate, the productwas obtained.

EXAMPLE l7 Pivaloyloxymethyl 6-[ (N-phenylacetyl-N-isopropylhydrazinomethyleneamino]-penicillanate Pivaloyloxymethyl 6-aminopenicillanate(6.6 g) and N'-isopropylphenylacetohydrazide (3.9 g) were stirred in dryether (200 ml) for 10 minutes at 05C. Propyl formimidate hydrochloride(2.8 g) was added and the mixture was stirred for 3 hours at O-5C andkept in the ice box for 16 hours. Thereupon the mixture was stirred for24 hours at room temperature and extracted with 0.05 N hydrochloric acid(2 X 200 ml). The acidic aqueous phase was treated with charcoal andextracted with ethyl acetate (2 X ml). The organic phase was treatedwith charcoal, dried and evaporated in vacuo to leave an amorphouspowder which was taken up in ether (100 ml) and extracted with 20%aqueous sodium bicarbonate (2 X 100 ml). The ethereal phase was treatedwith charcoal, dried and evaporated in vacuo. The residue did notcrystallize. NMR spectrum (10% w/v CD OD):

A. Pivaloyloxymethyl phenoxymethylpenicillinate To a suspension ofpotassium phenoxymethylpenicillinate (19.5 g) in acetone (200 ml),chloromethyl pivalate (8.3 ml) was added followed by 25% aqueous sodiumiodide (Sml). The mixture was refluxed for 5 hours and thereafterevaporated in vacuo. The residue was taken up in ethyl acetate (250 ml)and extracted with ice-water (50 ml), icecold 2% aqueous sodiumbicarbonate (2 X 50 ml) and finally with ice-water (2 X 50 ml). Afterdrying, the organic phase was evaporated to leave an oil which did notcrystallize. B. Pivaloyloxymethyl 6-(a-trimethylhydrazino-B-phenoxyethylideneamino)-penicillanate To a stirred solution ofphosphorus pentachloride (4.2 g) in dry, alcohol-free chloroform (40ml), quinoline (4.6 ml) and, after cooling to lC,' pivaloylox ymethylphenoxymethylpenicillinate (8 g) were added. After stirring for minutesat l0C, the solution was poured on an icecold saturated aqueous solutionof sodium bicarbonate (300 ml) with vigorous stirring. After stirringfor half an hour, the organic phase was separated and dried overmagnesium sulfate at 0C. After filtration, trimethylhydrazine (2.6 g)was added to the filtrate at l5C. The solution was kept at 0C for twohours and evaporated in vacuo. The residue was distributed betweendiluted hydrochloric acid (200 ml) with a pH of about 2.5 and ether (100ml). The aqueous phase was separated, made alkaline to a pH of about 7.5and extracted with ether. The ethereal phase was extracted twice withwater, dried, and evaporated in vacuo to leave an oil which did notcrystallize.

EXAMPLE 19 Pivaloyloxymethyl 6-(a-trimethylhydrazino-ethylideneamino)-penicillanate By following the procedure of Example 14 and re placingcarboxymethyl dithiophenylacetate by carboxymethyl dithioacetate, theproduct was obtained as an oil which did not crystallize.

EXAMPLE 2O Benzyl 6-trimethylhydrazinomethyleneaminopenicillanatehydrochloride By following the procedure of Example 1 and replacingpivaloyloxymethyl 6-aminopenicillanate by benzyl 6-aminopenicillanate,the compound was obtained as an amorphous powder.

EXAMPLE 21 6-Trimethylhydrazinomethyleneaminopenicillanic acidhydrochloride EXAMPLE 22 Pivaloyloxymethyl6-[(N'-benzyl-N,N-dimethylhydrazino)- methyleneamino]-penicillanatenitrate By following the procedure of Example 1 and replacingtrimethylhydrazine with 1benzyl-l,2-dimethylhydrazine the compound wasobtained as an amorphous powder.

What we claim is:

1. A compound of the formula I in which R R and R each represents alower alkyl radical optionally being substituted with phenyl, a loweralkcnyl radical, an acetyl, phenylacetyl or a carbamyl radical; Rfurther being represented by hydrogen in case that R, stands for acetylor phenylacetyl; each of the radicals R to R also can together with oneor more of the other radicals and any nitrogen atoms to which they areattached represent a ring system selected from the group consisting ofpyrazolinyl, pyrazolidinyl, l ,2,3,6-tetrahydropyridazinyl, 1,4,5,6-tetrahydropyridazinyl, hexahydropyridazinyl, piperidyl, morpholinyl,hexahydro-lH-azepin-lyl and hexahydro-l(2H)-azocinyl; R representshydrogen. methyl optionally substituted with phenyl'or phenoxy, a phenylradical optionally being chloro substituted, and a thienyl radical; Rrepresents hydrogen or lower alkyl or lower alkyl substituted withphenyl or lower alkanoyloxy or a salt thereof with a pharmaceuticallyacceptable acid.

2. Pivaloyloxymethyl 6-trimethylhydrazinome thyleneamino-penicillanate,or a salt thereof with a pharmaceutically acceptable acid.

3. Pivaloyloxymethyl 6-[(N-allyl-N,N-dimethylhydrazino)-methyleneamino]-penicillanate, or a salt thereof witha pharmaceutically acceptable acid.

4. Pivaloyloxymethyl 6-[(N-benzyl-N',N'-dimethylhydrazino)-methyleneamino]-penicillanate, or a salt thereof witha pharmaceutically acceptable acid.

5. Pivaloyloxymethyl 6-[ (N '-acetyl-N-isopropylhydrazino)-methyleneamino]-penicillanate, or a salt thereofwith a pharmaceutically acceptable acid.

6. Pivaloyloxymethyl 6-[(N'-carbamyl-N,N-dimethylhydrazino)-methyleneamino]-penicillanate, or a salt thereof witha pharmaceutically acceptable acid.

7. Pivaloyloxymethyl 6-[(5-methyl-2-pyrazolin-l-yl)-methyleneamino]-penicillanate, or a salt thereof with a pharmaceuticallyacceptable acid.

8. Pivaloyloxymethyl 6-[(N-(hexahydro-1H-azepin- 1-yl)-ethylamino)-methyleneamino]-penicillanate, or a salt thereof with apharmaceutically acceptable acid.

9. Pivaloyloxymethyl 6-[(N'-phenylacetyl-N-isopropylhydrazino)-methyleneaminoI-penicillanate, or a salt thereofwith a pharmaceutically acceptable acid.

10. A method for producing a compound according to claim 1, in which afi-aminopenicillanic acid derivative of the general formula 11:

in which R, is as defined above for R or stands for a trialkylsilylradical, e.g. a trimethylsilyl radical, is reacted with a compound ofthe formula 111:

in which R R R and R are as defined above, R is mild conditions, to formthe corresponding free acid of a lower alkyl radical and X is a goodleaving group, the formula I (R =hydrogen).

reaction optionally being followed by a cleavage, under

1. A COMPOUND OF THE FORMULA 1
 2. Pivaloyloxymethyl6-trimethylhydrazinome thyleneamino-penicillanate, or a salt thereofwith a pharmaceutically acceptable acid.
 3. Pivaloyloxymethyl6-((N-allyl-N'',N''-dimethylhydrazino)-methyleneamino)-penicillanate, ora salt thereof with a pharmaceutically acceptable acid. 4.Pivaloyloxymethyl6-((N-benzyl-N'',N''-dimethylhydrazino)-methyleneamino)-penicillanate,or a salt thereof with a pharmaceutically acceptable acid. 5.Pivaloyloxymethyl6-((N''-acetyl-N-isopropylhydrazino)-methyleneamino)-penicillanate, or asalt thereof with a pharmaceutically acceptable acid. 6.Pivaloyloxymethyl6-((N''-carbamyl-N,N''-dimethylhydrazino)-methyleneamino)-penicillanate,or a salt thereof with a pharmaceutically acceptable acid. 7.Pivaloyloxymethyl6-((5-methyl-2-pyrazolin-1-yl)-methyleneamino)-penicillanate, or a saltthereof with a pharmaceutically acceptable acid.
 8. Pivaloyloxymethyl6-((N-(hexahydro-1H-azepin-1-yl)-ethylamino)-methyleneamino)-penicillanate,or a salt thereof with a pharmaceutically acceptable acid. 9.Pivaloyloxymethyl6-((N''-phenylacetyl-N-isopropylhydrazino)-methyleneamino)-penicillanate,or a salt thereof with a pharmaceutically acceptable acid.
 10. A methodfor producing a compound according to claim 1, in which a6-aminopenicillanic acid derivative of the general formula II: